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Immediate and fatal 12V battery failure

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tfboy

Gimme the Caaaaaar!
Jan 7, 2016
79
20
Reading, UK
I searched and saw 12V battery failures are known, but from what I can tell, have just been a warning message which was dealt with a few weeks later when the car was booked in to have it checked.

12v Battery

Not so for me :(

I was going to a friend's house to demo the car. The outside temp getting close to freezing in the morning, I left home (around 60% SoC) and turned on max battery power to heat it up. I drove around 30 miles to the West Drayton store and service centre outside London to Supercharge. Left it there for around 40 minutes, left with about 93% SoC.

My friend lives about 15 miles away from West Drayton. I leave Tesla and make my way over there. About 10 miles / 15 minutes in, I get:
i-KHBGCzp-M.jpg


A minute or two pass, and the message goes away. Strange I thought, maybe just a glitch (I've had the odd one or two in my four months' ownership).

About 5 minutes later, I arrive at my friend's house, put the car in park, go in for a cup of coffee, do the sales pitch, we both come out to go for a drive and the car won't start, a whole string of messages continuously come up in a strange order, as if the whole car has crashed and stuck in a loop.

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I phone Tesla Service, we try a few reboots, shutdowns, resets, etc, but ultimately, unable to get it working. The tech on the phone thinks it was the 12V auxiliary battery which has failed / dropped below a minimun critical voltage beyond which it cannot do the safety checks and is unable to determine whether the main battery is OK or not and so, as a safety measure, disables the car.

That is something that cannot be overridden remotely, so they arranged to get the car on a flatbed trailer.

This was the "list" I ended up with:
i-QXPzgb2-M.jpg


It ruined my day, Tesla have potentially lost a £100k+ car sale and I'm now without my car.

Whilst I can accept failures do happen, what I do find totally unacceptable is how I've gone from an absolutely fine car to a warning message to an incapacitated car in under 15 minutes. So you guys who get a couple of weeks notice with no real issue, count yourself lucky, or myself incredibly unlucky.

As far as I'm concerned, this is a massive Achille's heel to the car and something that should be avoided. With all the tech and sensors in the car, if it's incapable of detecting what turns out to be a fatal battery issue with more than 15 minutes / 10 miles' driving is just unacceptable. :(
 
Can you or roadside hook up a jumper box to get the car drivable again?
Apparently no. I did suggest whilst on the phone to the support team whether I could jumper just to get the car started - even if just to drive the 15 miles back to the service centre.
Failing that, I suggested getting a ranger out (not sure they've ever offered that service in the UK), but again, wasn't possible. The ONLY suggestion was to get a trailer to load it up on which I did.

This morning, I get a survey questionnaire from Tesla asking how my support went.
i-z8x6HpV.png


You can imagine how I feel about that!

I phoned Tesla this morning for an update. The service agent looking after my case was apparently "busy" but would phone back immediately. It's now been three hours, I'm still waiting for that call.

It's a shame that when Tesla get it right, the customer satisfaction is just awesomely good. When they get it wrong however... Plus the "wrong" elements are things totally in their control, or at least you'd hope...
 
this was a "common" failure on the older models, it happened to me, but I thought the issue has been corrected and I was under the impression that this failure of the contacts rarely happens in the newer cars. sadly for you it appears that your car was one of the few that this happened to, on the bright side, you weren't stranded on the side of a roadway.
 
Surprising to see this sudden failure now. It happened with 2012-13 cars quite a bit. I believe the ultimate determination was the 12V battery producer. Tesla changed suppliers. When my warning came on after about 20 months of ownership, I called Tesla and they said there was no rush and to get it in within two weeks for a replacement. I had no problems. They just swapped out the battery.

What's the model, production date on the car?
 
I personally do not think this is a 12V battery failure. I have a friend with a 2012 Model S P85 who had a 12v battery warning for over a year and still managed to drive the car.

This must be a different component that failed. Please let us know what is the diagnosis. I have not yet seen a report of a contactor failure with the new inconnel contactors on the Ludicrous cars.
 
i wouldn't dismiss the possibility that this might be a 12 failure or something related to the dc-dc converter - and i'm surprised that you couldn't use jumpercables to start the car (assuming this is not a facelift model from the info in your signature). The poles to the 12v is behind the nosecone on older models, on the facelift you have to pop the hood (and this is not going to work if your'e out of 12v battery).

Going to be interesting to se the Teslas diagnosis on this issue - and hope you have your car back soon.
 
i wouldn't dismiss the possibility that this might be a 12 failure or something related to the dc-dc converter - and i'm surprised that you couldn't use jumpercables to start the car (assuming this is not a facelift model from the info in your signature). The poles to the 12v is behind the nosecone on older models, on the facelift you have to pop the hood (and this is not going to work if your'e out of 12v battery).

Going to be interesting to se the Teslas diagnosis on this issue - and hope you have your car back soon.


Not an isolated case, I had the same on a 2016 car a few weeks ago. Combination of cold and rain... Something on the main battery pack,
 
This does not sound like its only your 12v battery. Many of us have had the battery warning and 12v replacement. Mine was replaced within 4 months of ownership on a brand new Model S. When it was replaced, I was informed that it would last 1 to 1-1/2 years and will require replacement again. It's certainly an achilles heal for Telsa.
 
i wouldn't dismiss the possibility that this might be a 12 failure or something related to the dc-dc converter - and i'm surprised that you couldn't use jumpercables to start the car (assuming this is not a facelift model from the info in your signature). The poles to the 12v is behind the nosecone on older models, on the facelift you have to pop the hood (and this is not going to work if your'e out of 12v battery).

Going to be interesting to se the Teslas diagnosis on this issue - and hope you have your car back soon.
Use the emergency manual cable in the right front wheel well.
 
OK, after much chasing, Tesla have got back to me and clarified the diagnosis. It isn't the 12V battery, the lack of access to the main battery pack is in fact related to an isolation forced by a safety check. The short version is it's apparently the air conditioning unit that has developed a fault and is forcing the car into isolation mode.

Unless the car has a way of determining the voltage on the 12V battery, my guess is the tech on the phone assumed it was a 12V battery failure judging from the symptoms (car often forced into safety isolation if 12V battery is failing). In which case a jump leads or ranger wouldn't have been able to do anything.

My car is currently half apart as they try to replace the HVAC unit.

My biggest annoyance is I had a 1500 mile business road trip planned starting tomorrow, and it's uncertain yet whether car will be fixed in time in which case I need to make last-minute alternative arrangements...
 
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OK, after much chasing, Tesla have got back to me and clarified the diagnosis. It isn't the 12V battery, the lack of access to the main battery pack is in fact related to an isolation forced by a safety check. The short version is it's apparently the air conditioning unit that has developed a fault and is forcing the car into isolation mode.

Unless the car has a way of determining the voltage on the 12V battery, my guess is the tech on the phone assumed it was a 12V battery failure judging from the symptoms (car often forced into safety isolation if 12V battery is failing). In which case a jump leads or ranger wouldn't have been able to do anything.

My car is currently half apart as they try to replace the HVAC unit.

My biggest annoyance is I had a 1500 mile business road trip planned starting tomorrow, and it's uncertain yet whether car will be fixed in time in which case I need to make last-minute alternative arrangements...

I had these warnings on my X in the first two weeks and it had to be taken in twice on a flat bed. Originally they thought it was the connectors to the battery but it turned out to be a problem with the aircon (rear). It turned out that water had gotten in and caused a number of problems. They ended up swapping out a few bits and putting on a different cover to stop the water ingress.

Since then no issues but it took a few weeks of confidence building before I took it very far out of town.

The service centre were extremely responsive and gave me a loaner of a new model S while the car was being sorted which was fun.

Although it wasn't the best start after waiting for a year for my X the Manager of the service centre and his team were excellent and kept me informed at all stages.

If an organisation is defined not by the problems but how they respond to their problems then in my circumstance Tesla went to the top of the tree. I hope your experience is as good as mine was.
 
It's on page 24 of this First Responder's guide in the section about opening the hood. There are two release cables in the front wheel arch liners, one for the primary latch and the other for the secondary latch.

https://www.tesla.com/sites/default...16_Models_S_Emergency_Responders_Guide_en.pdf

Thanks for info - and sorry if this is off topic from the initial post o_O. Just a couple of questions if you have tried this - i thouht that facelifts (later than june 2016) didn't have a secondary latch - but it's reffered to in the above manual? And after you have pop'ed the hood, is it simply removal of plastic HEPA filter cover to access the 12v?

Sorry for beeing a noob on this ;) - since i don't yet have my model s to check for myself (delivery in feb2017)

In advance - thank you for all input, and @tfboy; happy to hear they found the problem on your car and that it is getting fixed.
 
To get the messages in text, so people in need can find this thread:

Car Needs Service - Car May Not Restart
Car Needs Service - Unable to Start Car
12V Power Low - Car May Shut Down Unexpectedly
Battery Power Very Low - Heating and A/C Reduced
Air Suspension Needs Service - Contact Tesla Service
Performing System Check - Please Wait

FWIW, I had all these except Battery Power Very Low and Air Suspension Needs Service, but had one other car function that "Needs Service" (I forget which), on a rented 2016 MS on a road trip (my own is waiting for a new windshield after a branch broke through it 3 weeks before our trip; Safelite dropped the ball on *that*).

The "Car Needs Service - Car May Not Restart" showed up first (right after supercharging to ~90%, in 95 degree weather which we had already been in for about 5 hours), and we drove about 90 miles to our destination. I called Tesla, but the main support number was useless; their callback system failed to call back, and when I did get someone he just said the car needed to go to a service center, leaving me to come up with the plan on how to do that, as it wasn't known if the car was driveable at that point. The tow truck guy hooked up a 12V battery (the screens weren't even on when he arrived, but turned on after the 12V battery was hooked up), but the car wouldn't drive, so we had to push the car to get it where the tow truck could pull it onto the flatbed. The only clue about an issue was that the AC fans seemed a bit weak before this, and a message 'limited due to settings' (or something like that) appeared when changing the AC settings.

We're in the middle of a trip from Massachusetts to South Carolina, and Tesla provided a loaner -- which may pose a problem if the car isn't ready today (in which case we'll either need to go 3 hours out of our way to return it on the way back on Tuesday, or figure out how to get back to Massachusetts and have the car get back to Massachusetts while the loaner gets back to South Carolina).

Assuming I find out what the issue is, I'll update here (and hopefully nobody will ever need it!).
 
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